Method for punching



Jan. 11, 1966 D. DANIELS 3,228,105

METHOD FOR PUNCHING Original Filed May 14, 1962 2 Sheets-Sheet 1 mm M qmmm @m r /V ON ON INVENTOR DENNIS DANIELS "W Y ATTO S Jan. 11, 1966 D.DANIELS METHOD FOR PUNCHING 2 Sheets-Sheet 2 Original Filed May 14, 1962x W? I \v 7 Q i fl E 2 r m I R ow mm mm mvzsw'roa DENNiS DANIELS BY I 5ATTORNEYS United States Patent 3,228,105 METHQD FOR PUNCHING DennisDaniels, W'illiamsviile, N.Y., assignor to Houdailie Industries, Inc.,Buifalo, N.Y., a corporation of Michigan Originai application May 11962, Ser. No. 194,485. Divided and this application Mar. 4, 1964, Ser.No. 356,682

5 Claims. (Cl. 29-525) This application is a division of applicantscopending application, Serial No. 194,485, filed May 14, 1962.

This invention relates to a method for making knockout structures.

Although the principles of the present invention may be included invarious devices of the unitized or subpress type of punch, aparticularly useful application is made in a punching apparatus which isadapted to construct knock-out structures in a sheet of material. Inparticular, when such devices have been previously provided, they havebeen characterized by their use of a relatively large number ofcomponents to make up the same.

The present invention is a method which may be practiced utilizing anextremely small number of tool parts.

Accordingly, it is an object of the present invention to provide asimple method.

Many other advantages, features and additional objects of the presentinvention will become manifest to those versed in the art upon makingreference to the detailed description and the accompanying sheets ofdrawings in which a preferred structural embodiment incorporating theprinciples of the present invention is shown by way of illustrativeexample.

On the drawings:

FIGURE 1 is a fragmentary cross-sectional view of a punching apparatusembodying a method provided in accordance with the principles of thepresent invention;

FIGURES 24 are enlarged fragmentary views, partly diagrammatic,illustrating the sequence of operations of the elements of the structureof FIGURE 1;

FIGURE 5 is a cross-sectional view of a slightly modified form of theapparatus embodying the method of the present invention;

FIGURE 6 is a fragmentary view, partly diagrammatic, illustrating theoperation of the device of FIG- URE 5; and

FIGURE 7 is a perspective view of a knock-out structure provided in afragmentarily illustrated sheet of material by the apparatus of FIGURE5.

As shown on the drawings:

The principles of this invention are particularly useful when embodiedin a punching unit such as illustrated in FIGURE 1 generally indicatedby the numeral 16. The punching unit 16 includes a rigid frame 11 whichsupports an upper fluid actuator operating head 12 and a lower fluidactuator operating head 13.

The frame 11 is here illustrated as being of the unitary or C-frame typeand includes an upper arm 14 and a lower arm 15. The arms 14 and 15 arerespectively provided with an upper reaction surface 16 and a lowerreaction surface 17 against which rigid reaction means schematicallyindicated at 18 and 19 may react. The arms 14 and 15 are respectivelyprovided with fluid passages 20 and 21 each adapted to be connected to asource of pressurized fluid. At their other ends, the fluid passages 20and 21 respectively communicate with the operating heads 12 and 13. Afurther line 22 is also adapted to be connected to a source of fluidpressure, and divides as illustrated, and communicates with both of theoperating heads 12 and 13. The upper arm 14 has a side 23 which isopposite to the reaction surface 16, and against which the operatinghead 12 is disposed.

3,228,105 Patented Jan. 11, 1966 Similarly, the lower arm 15 has a side24 which is opposite to the reaction surface 17, and against which theoperating head 13 is disposed.

The upper operating head 10 includes a cylinder 25 and a piston 26disposed within a chamber 27 in the cylinder 25. The piston is providedwith a seal such as an O-ring 28 which divides the chamber 27 into twoseparate sub-chambers, the upper one of which communicates with thepassage 29, and the lower one of which communicates with the line 22.The operating head It further includes a piston rod 29, the samecomprising in this embodiment an integral part of the piston 26, and atool which in this embodiment comprises a punch 30 integral with thepiston rod 29. At the opposite end of the cylinder 25, there is providedan annular portion 31 which is received within an annular groove in theside 23 of the upper arm 14, there being a sealing gasket 32 at thebottom of the groove. The cylinder 25 is secured to the upper arm 14 bya number of screws such as the screw 33 illustrated in the lower arm 15extending into the lower operating head 13. The upper cylinder 25further includes a rod-end 34 which has a lower surface 35 whichcomprises a stripping surface into which an aperture opens, the aperturebeing defined by guide means 36 which serve as a guide for the rod 29and punch 34). As explained below, the guide means 36 also comprises astationary die. The rod-end 34 of the cylinder 25 is also provided wthan O-ring 37 which seals the lower part of the chamber 27 by actingbetween the rod-end 34 of the cylinder 25 and the piston rod 29.

The lower actuator head 13 similarly includes a cylinder 33 having achamber 39 within which is disposed a piston 40. Connected to the piston40, such as integrally, is a rod 41, and connected to the rod 41, suchas integrally, is a tool 42 which here thus comprises a fluidly drivenpunch The chamber 39 is sealed at its lower end by a gasket 43 and atits upper end by a gasket 44 which comprises an O-ring, the chamber 39being divided into two sub-chambers by an O-ring 45 in the piston 49.Thus the upper part of the chamber 39 communicates with the line 22, andthe lower part communicates with the passage 21. The cylinder 38 has arod-end 46 having an outer upwardly directed surface 47 which normallysupports a workpiece W as shown. The support surface 47 is intersectedby an aperture defined by guide means 48 which guide the rod 41 and thetool or punch 42. The guide means 48 also comprise the main die of thisembodiment.

While the tools or punches 30 and 42 are normally both movable, undercertain circumstances, it may be desired to move only one of them,whereby one or the other may also comprise stationary tooling. The working ends of the tools 30 and 42 are complementally shaped throughout thearea defined by their cutting edges so as to be able to coact jointlywith each other on a portion of the workpiece VJ. To this end, theinstant tools 30 and 42 are provided with an undulated periphery whereinundulations of the tool 30 extend both below the surface 35 and up intothe guide means 36 whereby a portion of the edge of the guide means 36at such point serves as a die.

In order to operate the punching unit 10, fluid pressure is firstapplied to the line 22 to retract the pistons 26 and 40 to the positionsillustrated in FIGURE 1 for insertion of the workpiece W. Thereafter,fluid pressure is admitted only to the passage 20 which moves the piston26 downwardly as shown in FIGURE 2, thereby expelling fluid from theline 22. This movement continues until the punch 30 coacting with thedie or guide means 48 punches a slug S out of the workpiece W as shownin FIGURE 2. It is to be noted that the slug breaks entirely free andout of the workpiece W before the slug engages the tool 42. Furthermovement of the punch 30 causes it to coact with the punch 42 to formthe slug S into any desired shape. Since the tool 30 can enter the dieor guide means 48, it is evident that there must be the usual toolclearances therebetween. The forming operation performed on the slug Sis thus carried out at a location where the slug S is surrounded bytooling which is slightly larger than the punch which created it. It hasbeen found that the forming operation and/or continued downward pressureon the slug S by the punch 30 causes a slight growth in the over-allsize of the slug S without materially reducing its thickness.

When the operation diagramatically illustrated in FIG- URE 2 has beencompleted, pressure is released from the passage 20 and is applied tothe passage 21 which effects an upward movement of the piston 46 and thetool 42, thereby raising the slug S, the workpiece W which is clingingto the outside of the punch 36, and the punch 30. Fluid expelled fromthe chamber 39 passes into the lower portion of the chamber 27, and theraising of the piston 26 expels fluid from the passage 26. The upwardmovement continues until the workpiece W engages the stripping surface35, at which the movement of the workpiece W is arrested. Continuedmovement in the upward direction driven by the piston 46 and the rod 41causes the slug S to be reseated in the aperture in the workpiece Wwhich constitutes its point of origin. The extent of such reseating isdetermined by the effective length of the combined piston 26, rod 2d,and tool 36. In this embodiment, that length has been so selected thatthe central portion of the slug S has been returned to a position whereit is coplanar with the workpiece W, whereby the various undulations inthe slug S project from opposite sides of the sheet of material thatconstitutes the workpiece W. During the reseating operation, the punch42 and the die 36 serve as an assembling punch and die. Thereafter, thefluid pressure at the passage 21 is released and pressure is applied tothe line 22 to return the components to the position illustrated inFIGURE 1. If the workpiece W should tend to stick with a portion of theslug S projecting into the die 36, such tendency can be minimized oravoided by removing an extremely small amount of material from the dieor guide means 36 immediately adjacent to the surface 35, the same beingillustrated in FIGURE 4 in an exaggerated manner.

Where it is desired to construct a knock-out structure such as shown inFIGURE 7, the device of FIGURE 1 may be slightly modified for suchpurpose. Referring to FIGURE 7, there is disclosed a sheet of materialwhich comprises a workpiece W having a central slug C coplanar with theworkpiece W, and an annular slug A of undulated form disposedtherebetween. The undulated annular slug A has portions or undulationswhich extend alternately above and below the surfaces of the sheet ofmaterial that comprises the workpiece W. It is evident that where thecentral slug and the annular slug comprise a unitary piece, thestructure of FIGURE 1 may be utilized to construct the same. However,where these slugs are defined by a complete line of severancetherehetween, the punches, rods, and pistons of the FIGURE 1 form mustbe made hollow axially to provide internal guide and die means therein.Such a modification of the FIGURE 1 structure is illustrated in FIGURE5.

The punching unit of FIGURE is generally indicated at 49 and includes aframe 50 having a rigid upper arm 51 on which there is an upwardlydirected reaction surface 52 for engaging outside rigid reaction meansschematically indicated at 53. The upper arm 51 has a fluid passage 54which communicates with a fluid actuator operating head 55 which issecured to a side 56 of the arm opposite to the reaction surface 52.

In like manner, the frame 50 further includes a rigid lower arm 57having a downwardly directed reaction surface 58 eugageable withexternal outside reaction means schematically indicated at 59. The arm57 further includes a passage 66' which communicates with a lower fluidactuator operating head 61 secured to a side 62 of the arm 57 oppositeto the reaction surface 58. The operating heads 55 and 61 also havemeans for connecting each of them to a common pressure line 63.

The upper operating head 55 includes a chamber 64 within which there isdisposed an axially hollow piston 65 having an integral axially hollowrod 66 to which there is secured, such as integrally, a tool 67, whichhere comprises an annular fluidly reciproca'bly driven punch, the innerperiphery or edge of which also serves as a die as explained below. Thechamber 64 is defined primarily by a cylinder 68 which has a rod-end 69terminating in an outer cylinder surface 70 which extends up to andadjacent to the tool 67, and in which there is provided a recess whichdefines an external guide member 71 to guide the rod 66 or punch 67, thefixed guide '71 also serving to define the outer edge portion of anannular die. The operating head 55 further includes a further fixedguide means 72 secured to the upper arm 51 and extending through thepiston 65, rod 66, and tool or punch 67, and terminating at its lowerend in a support face 73 coplanar with the surface 70 and servingtherewith as a stripping surface. The guide means 72, is thus fixed andthe outer periphery of the member 72 adjacent to the surface 73 servesas an internal guide member for the rod 66 and tool 67, and also definesthe inner edge portion of an annular die along with the guide means '71,and still further also serves as a fixed punch as explained below.Suitable seals, such as O-rings and gaskets are provided for theoperating heads 55 and 61 as explained for FIGURE 1, these furtherincluding a seal 74 of the O-ring type to prevent leakage along thestationary central guide member '72. The interior of the hollow pistonrod 66 on the low pressure side of the O-ring 74 may be vented as at 75.

The lower operating head 61 similarly includes a cylinder '76 defining achamber 77 Within which is disposed an axially hollow piston '73 havingan integral axially hollow rod 79 to which is secured a tool 80, thetool 80 here comprising a fluidly reciprocably driven annular punchwhich also serves as a movable die. Similarly, the cylinder 76 isprovided with a rod-end 81 having a Workpiece supporting surface 82intersected by guide means 83 which externally guide the rod 79 or punch80, which means 83 define the outer portion of an annular die, beinggenerally similar to the guide means 71. The operating head 61 furtherincludes an internal fixed guide member 84 secured to the lower arm 57and terminating at its upper end in a support face 85, the outerperiphery of which is defined by means which serve as an internal fixedguide for the punch 80, and rod 79, which serve as a fixed punch, andwhich further serve to define the inner edge portion of an annular diealong with the means 83. The support face or backup surface 85 iscoplanar with the outer adjacent surface 82 on the cylinder 76.

The working ends or faces of the tools 67 and 80 are complemental toeach other and are shaped to form opposite sides of the annular slug Aof FIGURE 7.

The operation of this unit is the same as that described for FIGURE 1.Pressure is admitted to the line 63 which retracts the pistons 65 and 78to the position illustrated to enable the admission of a workpiece Wsupported on the surface 82.. Thereafter, this pressure is released anda high working pressure is applied to the passage 54 thereby advancingthe piston 65 so that the annular punch 67 passes through the workpieceW, and coacts with the annular die defined at 83 to create an annularslug A. Further advancement of the piston 65 causes the working ends ofthe tools 67 and 80 to bend or form the annular slug A to the desiredconfiguration wherein it is slightly enlarged on its outside diameterand formed to a slightly reduced hole size at its inside diameter.During this operation, the guide member 84 served as a punch along withthe inside diameter of the annular punch 67 which then served as a dieto thereby create the slug C which is forced upwardly into the hollowpunch or die 67.

Thereafter, pressure is relieved from the passage 54 and admitted to thepassage 68 to effect raising of the pistons 78 and 55 jointly with theannular slug A trapped therebetween, with the workpiece W clinging tothe outside of the punch 67, and with the central slug C clinging to theinterior of the punch 67, all as illustrated in FIGURE 6. This upwardmovement continues until the workpiece \V engages the stripping surface70 and the central slug C engages the support face 73. Further upwardmovement of the annular punch 80 drives the annular slug A into theworkpiece W and around the central slug C, pushing the punch 67 ahead ofit as it goes. The extent of such movement is limited by the effectivelength of the punch 67 determined by bottoming of its piston 65.Thereafter, pressure is relieved from the passage 60 and applied to theline 63 to return the annular punches to the position illustrated inFIGURE 5 as described previously. In view of the undulations in theannular member or slug A, some portions thereof extend upwardly abovethe plane of the surfaces 70 and 73 whereby the fixed annular diedefined therebetween coacts with the punch 80 to serve as an assemblingpunch and die.

It is thus evident that the central slug C and the annular slug A arefirst blanked by punching, and that there after the annular slug isformed such as with undulations, its outside diameter being increasedand its inside diameter being decreased while the same is entirelydetached from both the central slug C and the workpiece W. Further, itis evident that thereafter the annular slug A is re seated after havingbeen formed with its undulations extending out of the surfaces of theworkpiece W to a partial extent, and that the slugs C and A are returnedto their point of origin.

Although various minor modifications might be suggested by those versedin the art, it should be understood that I wish to embody within thescope of the patent warranted hereon all such embodiments as reasonablyand properly come within the scope of my contribution to the art.

I claim as my invention:

1. A method of making a knock-out structure in a sheet of materialcomprising the sequential steps of:

(a) punching a slug from the sheet;

(b) increasing the slug size by deformably reducing the thickness of theslug while it is entirely detached from the sheet, and

(c) driving the deformed slug back into the sheet at its point of originwith the slug engaging the sheet along the entire perimeter of the slug,and With the peripheral surface of the slug projecting from said sheetby an amount less than the thickness of said slug.

2. A method of making a knock-out structure in a sheet of materialcomprising the sequential steps of:

(a) punching a slug from the sheet;

(b) simultaneously forming and increasing the slug size by deformablyreducing the thickness of the slug while it is entirely detached fromthe sheet; and

(c) driving the deformed slug back into the sheet at its point of originto such an extent that the formed portion projects from said sheet by anamount less than the thickness of said sheet, While engaging the sheetalong the entire perimeter of the slug.

3. A method of making a knock-out structure in a sheet of materialcomprising:

(a) punching a central slug and a separate encircling annular slug fromthe sheet;

(b) increasing the outer and decreasing the inner dimensions of theannular slug by deforming the annular slug to reduce its thickness whileit is entirely detached from the sheet and the central slug; and

(0) driving the central slug only partially into the deformed annularslug, and driving the deformed annular slug back into the sheet at itspoint of origin.

4. A method of making a knock-out structure in a sheet of materialcomprising:

(a) simultaneously punching a central slug and 21 separate encirclingannular slug from the sheet;

(b) simultaneously increasing the outer and decreasing the innerdimensions of the annular slug by deforming the annular slug while it isentirely detached from the sheet and the central slug; and

(c) thereafter simultaneously driving the deformed annular slugpartially back into the sheet at its point of origin and around thecentral slug.

5. A method of making a knock-out structure in a sheet of materialcomprising:

(a) punching a central slug and a separate encircling annular slug fromthe sheet;

(b) therafter simultaneously increasing the outer dimension, decreasingthe inner dimension and providing formed undulations of the annularslug, all by deforming the annular slug while it is entirely detachedfrom the sheet and from the central slug; and

(c) driving the central slug into the deformed annular slug, and drivingthe deformed annular slug back into the sheet at its point of originwith the undulations projecting partially from each side of the sheet,and with the central slug disposed coplanar with the sheet.

References Cited by the Examiner UNITED STATES PATENTS 1,039,955 10/1912Keefe. 2,324,155 7/1943 Haynes 2203.2 XR 2,567,141 9/1951 Andrew et al.2,860,540 11/ 1958 Karlsson 29-522 XR WHITMORE A. WILTZ, PrimaryExaminer. CHARLIE T. MOON, Examiner.

1. A METHOD OF MAKING A KNOCK-OUT STRUCTURE IN A SHEET OF MATERIALCOMPRISING THE SEQUENTIAL STEPS OF: (A) PUNCHING A SLUG FROM THE SHEET;(B) INCREASING THE SLUG SIZE BY DEFORMABLY REDUCING THE THICKNESS OF THESLUG WHILE IT IS ENTIRELY DETACHED FROM THE SHEET, AND (C) DRIVING THEDEFORMED SLUG BACK INTO THE SHEET AT ITS POINT OF ORIGIN WITH THE SLUGENGAGING THE SHEET ALONG THE ENTIRE PERIMETER OF THE SLUG, AND WITH THEPERIPHERAL SURFACE OF THE SLUG PROJECTING FROM SAID SHEET BY AN AMOUNTLESS THAN THE THICKNESS OF SAID SLUG.
 3. A METHOD OF MAKING A KNOCK-OUTSTRUCTURE IN A SHEET OF MATERIAL COMPRISING: (A) PUNCHING A CENTRAL SLUGAND A SEPARATE ENCIRCLING ANNULAR SLUG FROM THE SHEET; (B) INCREASINGTHE OUTER AND DECREASING THE INNER DIMENSIONS OF THE ANNULAR SLUG BYDEFORMING THE ANNULAR SLUG TO REDUCE ITS THICKNESS WHILE IT IS ENTIRELYDETACHED FROM THE SHEET AND THE CENTRAL SLUG; AND (C) DRIVING THECENTRAL SLUG ONLY PARTIALLY INTO THE DEFORMED ANNULAR SLUG, AND DRIVINGTHE DEFORMED ANNULAR SLUG BACK INTO THE SHEET AT ITS POINT OF ORIGIN.